The Portable Document Format, or PDF, was originally developed by Adobe for use with its own Acrobat reader and editing software. PDF files are some of the most common types of documents, but now the task of opening them has shifted to web browsers. Some browsers can only view PDFs, while others can modify them and even add signatures.
So, how did web browsers end up being the main way to use and edit PDF files? It may seem like a strange match, or an example of feature bloat, but it’s one of the best success stories in the evolution of web browsers.
The Reign of Adobe Acrobat
Let’s start at the beginning. Adobe created the original PDF specification in 1993 as a technology for displaying pages on any screen and platform. It was mainly useful for the desktop publishing industry, where the size and positioning of images and text needed pixel-perfect accuracy.
Adobe made its own application for creating PDFs, called Acrobat, but it was priced at $50 —about $110 in 2025 dollars. Acrobat and the PDF standard didn’t catch on until Adobe made a free Reader application for read-only access to PDFs. Adobe co-founder Charles Geschke said in a 2008 interview, “The concept of giving away software was anathema, a very foreign concept. But it became obvious that doing that was the only way we could get market penetration. Microsoft could assume that somehow or another everybody had Word. We couldn’t assume that everyone was going to buy the Reader.”
When internet access and the web started going mainstream in the 1990s, PDFs were one of the best options for sharing documents with complex formatting. Adobe even created a Reader plug-in for web browsers, allowing them to display PDF files inside of web pages without switching to the full Reader application. PDFs became just as important for the web experience as videos and Flash animations.
Replacing the Plugins
Web browser plug-ins were an absolute nightmare for security and system stability. They were often not updated automatically, so even when security vulnerabilities were discovered and patched, the fixes didn’t roll out to most people for weeks or months. They could also cause crashes and performance issues in web browsers. Adobe’s Flash plugin was the biggest culprit for security issues, but Adobe Reader also had some problems over the years.
When web browsers started to phase out plug-ins in the late 2000s, they needed a replacement for the Acrobat plug-in, so web pages with embedded PDF content could continue working. Apple Safari switched to the native PDF viewer in Mac OS X, Firefox 19 arrived in 2013 with a built-in PDF viewer (the PDF.js project), and Google Chrome added a PDF viewer in 2010.
The migration away from Flash required significant updates to many websites, but the switch to built-in PDF viewers was much more seamless. Pages using tags like and to display PDF content continued working normally. Most people probably didn’t notice the transition, except the controls looking a bit different, but it was an important step for improving the performance and security of modern web browsers.
When web browsers finally turned off plug-ins in the 2010s, the built-in PDF viewers became the only way to show PDF files inside web pages. Documents that needed Acrobat-specific functionality, like scripting, had to be downloaded and opened in the desktop Acrobat application or another tool.
The built-in PDF viewers have become better over the years. For example, Firefox’s viewer can now add text, markings, and signatures to PDF files. Microsoft has gone full-circle with its Edge web browser, which now uses an Acrobat-based reader for PDF content developed in collaboration with Adobe.
Not Just for the Web
Now that web browsers had their own built-in PDF viewers, which were a necessary component for moving away from plug-ins across the web, the next logical step was allowing them to be used with local files. That way, a web browser could fully replace Adobe Acrobat and other applications for opening PDFs.
Over time, Firefox, Google Chrome, Safari, and other web browsers added themselves as valid applications for opening PDF files. When you double-click on a PDF file on a computer today, it usually opens in a web browser. Mac computers still have Preview for opening documents like PDFs, but the only built-in viewer on Windows 10 and 11 is Microsoft Edge.
It might seem a bit weird that web browsers have taken over PDF file handling on most computers, but it’s not a case of software bloat. Web browsers had to create their own viewers to move away from plug-ins, and by extending that functionality to local files, they could replace apps like Acrobat Reader for typical usage. Personally, I’m happy to keep the Adobe software on my computer to a minimum.
